A problem created in a crankcase as the result of blow-by gases mixed with oil is known, by way of example, from DE 234479. In internal combustion engines, it is fundamentally impossible to avoid the passage of a certain amount of combustion gases mixed with oil or liquid fractions of oil between a working piston and a combustion cylinder, into an interior space of the crankcase. The abovementioned document suggests suctioning off corresponding blow-by gases via a fan. In order to prevent oil fractions from depositing in the fan or in subsequent connector parts, the prior art document suggests attaching a cooler in the form of the fan for the purpose of allowing the oil fractions to condense. The condensed oil fractions are made usable once more by the same flowing back into the crankcase by means of gravity in a suitable uptake tube. However, the problem with this approach is that the separation of oil from the blow-by gas must take place at a position in the crankcase with a sufficient geodetic height to enable the gravity-supported return flow of the oil.
One solution known from DE 2845955 works around this problem by suctioning the blow-by gas along with the oil vapors out of the crankcase and into a forced circulation loop of one of the media of the engine. For this purpose, a Venturi tube is arranged in the oil system between the oil pressure outlet for the lubricating oil and the oil pan. A Venturi tube can alternatively be arranged in a loop of the precompression air as well, such that the oil vapor is carried by the flow of the precompression air, and in this manner is routed back into the cylinder. The latter can also be configured to utilize an auxiliary line excluded from the force circulation loop. However, this configuration has the problem that—as mentioned above—the oil fractions in the blow-by gas contaminate the subsequent fans, compressor, and other lines and means of conveyance in the forced circulation loop.
The above mentioned disadvantages can be avoided by a proposed separation wall for the routing of blow-by gas and the separation of oil. A suitable separation wall is included in DE 10128465 A1, by way of example, and is formed by means of a vaned wheel arranged radially to a crankcase. In a principally advantageous manner, this solution is based on the concept of evacuating the blow-by gas from the crankcase while separating oil out of the blow-by gas. Such a conceptualization prevents the very undesirable contamination of the periphery of an internal combustion engine. However, it is desirable to implement this concept in a simplified manner.